Electric discharge device



Feb. 6, 1940.

V. K ZWORYKIN ET AL ELECTRIC DISCHARGE DEVICE Original Filed Jan.3l, 1936 lhmcnEors VladmirD. Zworyiizn 'ou is Mal ter Mmw Patented Fable, 1940. a

- UNITED sT TEs t 2,189,305 I 'ELEcra c msonmcn DEViCE Vladimir K. Zworyk in, Philadelphia, Pa. and

Louis Malter, Newark, N. Jqassignors to Radio Corporation ofAmerica; a

. ware corporation of Dela- Original application January-3 1 .1936, Serial No. 61,680, now Patent No. 2,150,573, dated March 14, 1939. Divided and this application Septeni bet 8, .1938, Serial No. 228,900 t I 8 Claims. (01. zso-se) Our invention relates to electronic oscillators and multipliers; More specifically, our invention is anelectronic oscillatoror amplifier in which the number of electrons ismultiplied by secondary emission.

This application is a division of our Patent No. 2,150,573, which issued March 14, 1939 on a copending application, Serial No. 61,680, entitled Electric discharge devices and filed January 31,1936.

We are aware of numerous ultra high frequency oscillators which operate as electronic oscillators. Oscillators of this type are broadly .known asmagnetrons, or Barkhausen-Kurz oscillators. We are also awareof electronic multiplication devices in which secondary emission increases the total number of electrons flowing in a given circuit. Amongthe' objects of the present invention is to combine. the operating characteristics of a magnetron oscillator or amplifier and an electron multiplier."

Another object is to generate ultrahigh frequency oscillations ina vacuum tube employing cold electrodes which are secondarily emissive. An additional object is to couple a. driver circuit which is energized by the emission of secondary electrons to an oscillatory circuit where-'- by sustained oscillations are established. .A still further object is to devise an electronic oscillator-multiplier device. employing electrostatic fields only. Additional objectsiwill appear in the accompanying specification and: appended claims. In the accompanying drawing, 1 Figure 1 is a schematic dia ram of an electronic oscillator device, f. l Fig. 2 is a modified iorml of oscillator utilizing hollow electrodes, and v A i Fig. 3 is a further modification of the hollow electrode oscillator. r f l The theoryoioperation of our invention involves an understanding of electronic oscillators,

secondary emission and electronic multipliers. The theory of the operation of these devices is complicated and not thoroughly, understood. However, since the theory may bean aid to an understanding of our invention we shall present a tentative theory of operation but do not intend to thereby limit our invention.

In an electronic oscillator of the split anode type, electrons are emitted by a heated cathode. Under the. influence of a magnetic field whose lines of force surround the cathode and are substantially parallelthereto the electrons, emitted by the cathode, follow a icurved path from ,the cathodetoward theanodes. :11. the magnetic field We propose to combine whereby a single devicemay be used as an. elecably of annular or toroidal shape.

is of suitable strength, theltransit time ofelectronswill be such that ultrahigh frequency oscillations will be established ina tuned circuit connected between the anodes. The frequency of such oscillations dependsprimarily upon the Q magnetic field' strength. The oscillatoryfre quency may also depend on the resonant period of the circuit connected to-the anodes.

The theory of secondary emissionis as-follows:- If electrons moving athi'gh velocity strike an electrode surface, secondary electrons are emitted. The number of such secondary electronswill depend upon the velocity of impact and the nature of the surface material of the electrode upon which the primary electrons impinge. I. l

The theory of electronic "multipliers is based primarily upon the theory of secondary emissidn. If primary electrons impinge at sufiicient velocity on a suitable electrode, this electrode will emit a large numberof secondary electrons.

These electronsmay be accelerated and impinged on 'a second electrode which in turn will emitstill more secondary electrons. In' this manner the number of electrons maybe increased and multiplied many fold.

several of thesexeffects tronic oscillator-multiplier. One device embodying our invention is. illustrated in Fig.1. In Fig. 1 the evacuated envelope 5! is preferinner and outer, circular walls of this envelope aresuitablymounted atintervals four gridlike electrodes 53. Each of these electrodes is made secondarily emissive. electrodes are connected'tog ether by leads 55. and 51. Between these leadsis serially, connected a tunable circuit 59 and an accelerating voltage source 6|. Thetunable circuit comprises aninductor 63 and a variable capacitor 65. V

g The magnetic field isapplied so that its lines of force are substantially parallel to thesurfaces of the grid-like electrodesi The electron path is substantially circularand is represented. by the dash line 61. a g H The theory of operation of this circuit will now be given. Under the accelerating influence of the magnetic fieldand. the positively charged elec-. trodes, primary electrons will be emitted from thexnegative electrodes. These electrons will strike the positively charged grids and will emit secondary electrons. If the. tunable circuit: is

resonant and if itskratiopf reactanceto resist- Oppositely disposed Within the will be such as to result in the building up ofsustained oscillations in the tuned circuit.

Fig. 2 is a schematic illustration of our inven tion in which electrostatic forces only are employed. In this figure, within a suitable envelope 9| four hollow electrodes, 93, are arranged to form a substantially rectangular path. Each of these electrodes resembles a hollow L or a hollow irregular T. The hollow section of each ofthese.

electrodes may be a circular section. It will be observed that the several electrodes have three openings at the ends thereof. oppositely disposed pairs of these electrodes are joined by connecting wires 95 and 91. Between these wires, 95, 97, are serially connected a tunable circuit 99 and a battery It I. The tunable circuit comprises a variable capacitor I03 and an inductor I05. The ratio of the reactance to the resistance of this circuit should be high.

The theory of operation of this circuit is substantially the same as that of Fig. 1.- It is assumed that electrons will be emitted from each of the instantaneous negative electrodes and will be accelerated at high velocity toward the instantaneously positive pairs of electrodes. The surfaces of these electrodes, which act as targets, are made secondarily emissive and liberate increased numbers of secondary electrons. These secondary electrons are in turn accelerated at high velocities toward the next succeeding instantaneously positive electrodes. The electron paths are represented by the dash line Ill'I.

It will be apparent that the instantaneous voltage of the tunable circuit 99 must exceed the voltage of the battery IDI if sustainedoscillations are-to be generated. If this circuit is resonant and has a low resistance in relation to its reactance, the currents flowing in the resonant circuit will be sufficient to establish the required 7 I between successive electron movements or multiples thereof.

In Fig. 3 the envelope 9| and the electrodes III, H3, H5, H1 are similar to those of'Fig. 2. The circuit arrangements illustrated by this figure differ from those of Fig. 2. In the present circuit, each of the adjacent electrodes beginning with III are connected as follows: An oscillatory circuit I I 9 is connected to the first electrode I I I and to the negative terminal of a battery I2 I. The positive terminal of this battery is connected to the second electrode IIS. The negative terminal of the battery I2If also is connected to a second oscillatory circuit I23. This oscillatory circuit I23 in turn is connected to the third electrode I I5 and to a third oscillatory circuit I25. This oscillatory circuit is connected to the negative terminal of a second battery I21. The positive terminal of battery IZ'I connects to the fourth electrode II'I. I2'I is also connected toafourth oscillatory circuit I29. This oscillatory circuit is connected. to the first mentioned electrode III. v

Of these oscillatory circuits, the first and third mutual magnetic coupling M or the like.

vides the necessary force.

The negative terminal of batterymentioned I I9, I25 are the circuits which deliver energy to the electrons resulting in secondary emission, the second and fourth mentioned circuits I23, I29 are the circuits which abstract energy from the electrons so as to maintain oscillations .within these circuits. The circuit III) and the circuit I29 are suitably coupled by The circuit I23 and the circuit I25 are likewise coupled. No magnetic field is required in this circuit arrangement. The electrostatic field pro- In this arrangement, electrons emitted from the instantaneously negative electrodes approach the next adjacent instantaneously positive electrode but do not strike this target as the'instantaneous polarity changes during the electron movement so that the next succeeding target is struck by the electrons at high velocities. The impact of these electrons liberates secondary electrons which are in turn carried around the electron path I3I. The mutual coupling between the pairs of oscillatory circuits provides the necessary feedback path by means of which sustained continuous oscillations are generated.

It should be understood that various combinations of parts which are represented in the several illustrations of our invention may be combined, also a thermionic oscillator may be employed in connection with any of the embodiments illustrated in the figures in order to provide a driving voltage. Likewise, an amplifier coupling may be employed to couple the oscillatory circuits of any of the several figures.

Although we have illustrated electronic de-- This particular shape is not essential and plane electrodes may be substituted.

Other modifications within the scope of our invention will occur to those skilled in the art. The foregoing examples are by way of illustration of our invention and are not to be taken as limitations of form or circuit.

We claim:

,1. In an electronic oscillator-multiplier at least four electrodes having electron emissive surfaces, said emissive surfaces being the principal source of electron emission for said oscillator-multiplier, means electrically connecting alternately disposed electrodes, an oscillatory circuit and a source of polarizing potential serially connected between two adjacent emissive electrodes, so that electrons impinge on each electrode and release secondary electrons which pass to an adjoining electrode in a predetermined sequence.

. 2. In an electronic oscillator-multiplier at least four electrodes having electron emissive surfaces, said' emissive surfaces being the principal source of electron emission for said oscillatormultiplier, means electrically connecting alternately disposed electrodes, and means for impressing a fixed biasing potential and asuperimposed alternating potential between adjacent emissive electrodes, so that electrons impinge on each electrode and release secondary electrons which pass to an adjoining electrode in a predetermined sequence.

3. In an electronic oscillator-multiplier at least four electrodes having electron emissive surfaces, said emissive surfaces being the principal source of electron emission for said multiplier-oscillator, means electrically connecting alternately disposed electrodes, means for impressing a fixed biasing potential and a super imposed alternating potential between adjacent emissive electrodes, and means for creating a magnetic field whose lines of force intersect said electrodes.

4. A device of the character described in claim 1 in which said emissive electrodes are hollow members having their inner surfaces electron emissive.

l 5. A deviceof the character described in claim 1 in which said emissive electrodes are grid-like structures arranged mutually at right angles to each other.

6. In an electrical discharge device an evacuated envelope, a plurality of hollow electrodes supported in symmetrical relation within said envelope and including electron emissive inner surfaces, an oscillatory circuit, a source of biasing potential, and means connecting said oscillatory circuit and said course of biasing potential between pairs of said electrodes, said electrodes having adjacent openings so that a continuous electron path is formed through each of said hollow electrodes insuccession.

7. In an electronic oscillator-multiplier, an annular shaped evacuated envelope, a plurality of grid electrodes disposed in said envelope at substantially uniform intervals, means ;for renemitted from said surfaces travel in curved paths between said electrodes and sustain oscillations in said circuit.

8. In an electrical discharge devicean evacuated envelope, a plurality of hollow electrodes supported in symmetrical relation within said envelope and including electron emissive surfaces, a plurality of serially connected'oscillatory circuits, means respectively connectingsaid hollow electrodes to thecommon terminals of said oscillatory circuits, whereby a 'con'tinuouselectron path is established through said hollow electrodes, and continuous oscillations are generated. 1

VLADIMIR. K. ZWORYKIN.

LOUIS ALTER, 

